1. Field of the Invention
The invention relates to an electronic apparatus for authenticating the user of the electronic apparatus and an authenticating method of the user.
2. Description of the Related Arts
In recent years, in association with the realization of a light weight and the miniaturization of electronic parts, electronic apparatuses which are used by being attached to bodies of the users are extensively being developed. They are also called wearable (attachable to the body) electronic apparatuses. For example, there are electronic apparatuses of various forms such as watch, necklace, ring, bracelet, and headset. A wearable electronic apparatus of a watch type has been disclosed in JP-A-2002-125039.
FIG. 1 shows an external appearance of the watch type electronic apparatus disclosed in JP-A-2002-125039. The electronic apparatus of FIG. 1 is constructed by an apparatus main body 101 and a wristband 102 retained to both end portions of the main body 101. A display unit 103 to display various information is provided in an almost center portion of an upper surface of the apparatus main body 101. Buttons 104a, 104b, and 104c to operate the watch type electronic apparatus are provided in a lower portion of the upper surface of the apparatus main body 101. Further, a plurality of small buttons 106 to input information are provided in an extending portion 105 extended from the lower portion of the apparatus main body 101. An antenna (not shown) is provided in the apparatus main body 101, so that it is possible to communicate with a parent terminal (cellular phone terminal).
Although such an electronic apparatus is small and convenient to be carried around, there is a risk that it is abused by a stranger when the user leaves the electronic apparatus, or the like. In the electronic apparatus as mentioned above, therefore, it is often controlled to require the user to input a user ID, a personal identification number (PIN), or the like when a predetermined operation is executed. In an apparatus such as an electronic apparatus in FIG. 1 having a function for communicating with the outside, also in the case of starting the communication, it is necessary to input the user ID and the PIN for the purpose of assuring security of the transmitting side and the receiving side. In the electronic apparatus of FIG. 1, the user is required to input the user ID and the PIN by pressing the buttons 106 several times, thereby guaranteeing by the personal authentication that he is a rightful user.
However, since a size of each button 106 is very small as shown in FIG. 1, there is a high possibility that the user misinputs the information. If he misinputs the information, a message or the like showing that the inputted user ID and the PIN are wrong is displayed and he has to input the correct information again. Therefore, he needs to carefully input the correct user ID and the PIN in order to avoid such a wasteful reinputting operation.
Since such personal authentication as mentioned above is often required every predetermined operation or communication of the electronic apparatus, the user has to execute the inputting operation each time with the small buttons. Those operations are extremely annoying and stressful to the user and, at the same time, he feels a serious psychological stress. The more frequently he uses the electronic apparatus, the more stressed he feels.